I propose studies of the development of ingestive behavior. Ingestion is one of the few behaviors that can be studied from birth throughout the life of altricial mammals. As such, it provides a powerful tool for the analysis of behavioral and neural development. These studies will take advantages of techniques that we have developed for study of developing ingestive system of rats, away from the suckling situation. Our tests allow tight experimental control and avoid potential problems created by the special nature of suckling. Specifically, the development of (1) sensory modulation, and (2) physiological controls of ingestion will be studied. Sensory deprivation may contribute to the effects of food deprivation procedures, and this potential factor in the development of ingestive behavior will be investigated (3). In addition, I will assess the importance of specific and defined early oral experiences (4). These studies continue to examine a behavioral system for early ingestion that appears to be the precursor to adult ingestive behavior. It is a system which can provide a unique study arena for assessing neural and behavioral development. I propose here to begin relating brain development to behavioral changes in the developing ingestive system. One initial approach will utilize brain transections, a second, measurement of regional brain metabolic activity using the 14C-2DG autoradiography technique. The proposed projects treat ingestive behavior in pups as a general model of motivational development. Thus, they may provide a representative ontogenetic analysis of a system in which behavioral and neural development can be examined and integrated.